This invention relates to the improvements in track shoes for track-type vehicles and particularly to low ground pressure shoes designed for use in medium-light or medium-wet soils.
Modifications to track shoes have been proposed to improve the floatation and traction capabilities in light or very wet soils. For a given width and length of a track shoe, a number of these modifications involve varying the shape of the ground contact surface of the shoe. Such modifications usually incorporate a protuberant traction face which has a generally V-shaped or triangular face for engaging the ground.
With some types of low ground pressure shoes, the V-shaped traction face is blunt enough or obtuse enough to provide good floatation in light soil, but suffers from not having sufficient projection depth to provide good traction.
On the other hand, some type of low pressure shoes may have a projecting traction ridge running the length of the shoe to provide traction. However, with such designs the turning resistance is necessarily greater due to the projecting ridge which is in engagement with the soil. Further, the space between the ridge and other parts of the shoe and/or adjacent shoes can fill and become compacted with mud or soil to the extent that the effectiveness of the traction ridge is much reduced.
It would be desirable to provide a low ground pressure shoe which, while presenting a large surface area to reduce ground pressure, would also incorporate a traction ridge member that provides a lower turning resistance as well as self-cleaning capability to prevent mud and soil from building up on the shoe and reducing the effectiveness of the design.
It has been found that some types of V-shaped or triangular type low ground pressure shoes suffer from the disadvantage of imparting intermittent shock loading to the track support structure or portions thereof. This is due to the fact that triangular type shoes have a projecting apex which is the first portion of the shoe to come into contact with the ground. Obviously, a triangular type shoe that must initially support the weight of a vehicle on its apex is unstable and will tend to rotate to one side or the other of the apex as the shoe sequentially passes beneath, and bears the weight of, each track roller. This is especially true when the track is operating on a hard surface.
The tendency of the shoe to rotate about the apex is, and must, be resisted by the particular members in the track (e.g., pins and links) to which the shoe is secured. During operation of the track, the shoes tend to rock about the apex so rapidly that the resulting moments and forces transferred to the track links and pins are actually in the nature of deleterious shock loadings. Such shock loadings can produce an undesirably high component wear rate. Thus, it would be desirable to provide a shoe which has the advantages of a triangular traction face yet does not generate high shock loads in the track components.